Ping watchdog thread during GpuChannel destruction

gpu/command_buffer/service/memory_program_cache_unittest.cc

Index: gpu/command_buffer/service/memory_program_cache_unittest.cc
diff --git a/gpu/command_buffer/service/memory_program_cache_unittest.cc b/gpu/command_buffer/service/memory_program_cache_unittest.cc
index a4a78c6299078af5dd2595aaa5fc8fb84dce4e07..86e707bcca0d1648345b24de2b1c5f6505d6bb5e 100644
--- a/gpu/command_buffer/service/memory_program_cache_unittest.cc
+++ b/gpu/command_buffer/service/memory_program_cache_unittest.cc
@@ -81,7 +81,9 @@ class MemoryProgramCacheTest : public GpuServiceTest {
         fragment_shader_(NULL),
         shader_cache_count_(0) {
   }
-  ~MemoryProgramCacheTest() override { shader_manager_.Destroy(false); }
+  ~MemoryProgramCacheTest() override {
+    shader_manager_.Destroy(false, nullptr);
+  }
 
   void ShaderCacheCb(const std::string& key, const std::string& shader) {
     shader_cache_count_++;